Interim Pension and Other Postretirement Benefits (Table)

3 Months Ended

Dec. 31, 2015

General Discussion of Pension and Other Postretirement Benefits [Abstract]

Components of net periodic pension cost table

The components of our net periodic pension cost for our pension and other postretirement benefit plans for the three months ended December 31, 2015 and 2014 are presented in the following table. Most of these costs are recoverable through our gas distribution rates; however, a portion of these costs is capitalized into our gas distribution rate base. The remaining costs are recorded as a component of operation and maintenance expense.

	Three Months Ended December 31
	Pension Benefits						Other Benefits
	2015			2014			2015			2014
	(In thousands)
Components of net periodic pension cost:
Service cost	$	4,698		$	5,051		$	2,706		$	3,896
Interest cost	7,095			6,699			3,106			3,596
Expected return on assets	(6,881		)	(6,436		)	(1,566		)	(1,608		)
Amortization of transition obligation	—			—			21			68
Amortization of prior service credit	(57		)	(49		)	(411		)	(411		)
Amortization of actuarial loss	3,320			3,917			(542		)	—
Net periodic pension cost	$	8,175		$	9,182		$	3,314		$	5,541

Schedule of assumptions used table text block

The assumptions used to develop our net periodic pension cost for the three months ended December 31, 2015 and 2014 are as follows:

	Pension Benefits				Other Benefits
	2015		2014		2015		2014
Discount rate	4.55	%	4.43	%	4.55	%	4.43	%
Rate of compensation increase	3.50	%	3.50	%	N/A		N/A
Expected return on plan assets	7.00	%	7.25	%	4.45	%	4.60	%